1. Field of the Disclosure
The disclosure relates generally to vibration testing.
2. Brief Description of Related Technology
Vibration testing of very flexible, light, or lightly damped structures is often conducted by exciting the structure without contact. Noncontact excitation avoids adding mass, stiffness, or damping to the test structure. One example of noncontact excitation is acoustic-based excitation. Speakers are used to provide the excitation force. However, such acoustic excitation systems are only capable of transmitting very low forces and very low amounts of power to the test structure.
Speaker-based excitation systems may also be unsuitable for excitation of structures with complex geometry due to space constraints. Speakers are not practical for excitations at high frequencies due to the large amount of power involved. The large power may be available, but the power comes at the cost of large size. The large size of the test system may render the acoustic approach impractical for structures with complex geometry. For example, acoustically exciting the blade of a turbomachinery bladed disk at high frequencies may not be possible because the speaker has large size and thus cannot fit between two adjacent blades.
Other excitation systems provide mechanical excitation via direct contact. For example, the use of stingers may provide direct forces to the excited structure. However, these methods involve contact between the stinger and the structure being tested. The properties of the test structure (e.g., mass, stiffness, and/or damping) may be changed due to interaction with the stinger.